Radon Monitoring
Radon gas comes from the breakdown of radioactive material in the earth. It is an odorless and colorless gas that can leak through any crack or hole in the foundation of a home. It can build up over time to hazardous levels. The Environmental Protection Agency (EPA) has determined a level over 4.0 piC/l (pico Curies per liter) may be considered hazardous. Exposure to levels higher than 4.0 piC/l over time can cause lung cancer, especially in smokers.
Radon gas has been detected in all 50 states. Some areas have higher levels than others. The EPA website (http://www.epa.gov/radon/zonemap.html) shows how levels can vary across the U.S. The levels in your home can differ from the levels in your neighbor's home. The only way to determine these levels is to have your home tested.
Radon monitoring can be done in two ways: Active and Passive. Active monitoring is typically short term, and is the type usually done to satisfy a contingency of a home purchase contract. A radon monitor is left in the lowest lived in level of a home, usually a basement, for at least 48 hours. During the monitoring period, a "closed home" condition should be observed. The windows need to be closed during the this time period. Doors can be used, but should not be left open for any length of time. Furnaces and air conditioners can be used as normal. The monitoring should also not be performed during high winds or heavy rains, as these can affect the results. Passive monitoring is a longer time period, anywhere from one week to one year. This involves leaving a canister in the lowest lived in level. These canisters can be purchased at most home centers and can be performed by the homeowner. They may also be available for purchase at your county health department. After the predetermined time, the canister is sent to a licensed laboratory for analysis. Passive monitoring usually cannot be completed in time to satisfy a home purchase contract contingency. The EPA website (http://www.epa.gov/radon/radontest.html) has information on the different type of tests and testing devices.
I use a Sun Nuclear Model 1027 continuous radon monitor. The monitor takes samples each hour, and calculates an average for the monitoring period. The results are printed out at the end of the monitoring period. On the printout, each samples number is printed so the high and low numbers are shown. If possible, I try to place the monitor in the home in advance so I can print the results at the time of the home inspection.
Depending on the levels of radon that are detected, there are different option for mitigation. The areas can be ventilated, or sealed to limit the amount of gas getting in, or a combination of these can be used. A professional radon mitigation company can determine what option would be best for the home, and can provide you with an estimate of the costs involved. Through proper mitigation, radon levels in the home can be lowered to acceptable ranges.
Please contact me if you have any questions about radon, or to find out the costs of radon testing.